Re: tcp counters


CLYNN@G.BBN.COM
25 Feb 1987 21:16-EST


Mike,

For TOPS-20 systems running the BBN network software, a "lowly user"
should first try TSTAT; it doesn't give error counters, but may give
insight about hung connections. If run a user runs it under the same
job as the one owning the problem connection, give it JOB; otherwise
just a <return> to see all connection & find the one(s) of interest.
By looking twice, one can see changes in sequence numbers, windows,
and round trip time.

@tstats
TCB ID: >
J/L JCN/Id Flg State Sequence Una Wndow RTT/MxS Un/Baud Net+Host Port
 14. 4. R:O EST 21132187. 2465. 107. 0. F:128.89.0.87 0.23
      78. S:OV EST 933691537. 0. 1932. 964. 34C L:192.1.2.67 131.135
 5607674
  0. 6. R:O EST 11965583. 2630. 404. 176. F:192.1.2.12 0.9
 66 3236. S:OV EST 87128682. 0. 363. 536. 12C L:192.1.2.67 0.23
 5624271
@

If that doesn't show what is happening, other per-connection information
can be examined, by name, using either the .IPRIP function of the IPOPR%
jsys, the .TCRTC function of the TCOPR% jsys, or the STAT% jsys (TSTATS
uses the IPOPR% jsys).

TCRPC # pkt received TCSPC # Pkt sent
TCIGN # pkts ignored TCRXP # Pkt retransmitted
TCDUP # duplicates recvd TCRZW # retransmitted into 0 window
TCROS # out of sequence
TCRST # RST received TSTO Send time out(ms)

TCICM # ICMP msgs recvd TCABI aborted due to inactivity
TCIDU # Dest unreachable TCABR aborted due to RX timeout
TCIPB # Parameter problem TCERR TOPS20 error code
TCIRD # Redirect msgs recvd TERR BBN error code
TCISQ # Source Quench msgs recvd
TCITE # Time exceeded

A program which shows many of these (but which requires wheel capabilities
for other reasons) is TCPEEK; it wants the ID and TCP connection block
address (as listed by TSTATS):

@tcpeek
~ TCB ID(10): 3236 MONITOR ADDR(8): 5624271
TCBID TJCN TOWNR TOFRK TFH TFP TLH TLP TSMRT TRXP TSTO
3236 6 0 6 #30000201014 #11 #30000201103 #27 404 #0 900000
TERR TSTAT TVTL
#0 #2077164 #66
TRIS TRLFT TRLAK TRWND TRLWN TRURP TRBS
11965292 11965583 11965583 2630 11968213 11965292 0
TCRCV TCRPC TCDUP TCIGN TCROS TCRZW TCEWN TCPCC TCRST TCRPU TCRUR
0 526 0 0 0 0 0 0 0 0 0
TSIS TSLFT TSSEQ TSWND TSURP TSBYT TSCB TSCPK
87097344 87128682 87128682 363 87128377 0 #0 #0
TCSND TCSPC TCRXP TCRXF TCPZA TCFWN TCFWT TCSPU TCSUR
0 633 76 13 167 30 7314 625 3
TCICM TCISQ TCIRD TCFWP
0 0 0 0
TSMXS TCRTM TCATM TCLTM TCBTP TSPRB
536 43589016 44220791 47535287 47535287 44220791
TCSAG TCFAK TIFDF TTTL TTOS TABTF TCABI
0 0 0 60 #0 #0 0

~ TCB ID(10): 78 MONITOR ADDR(8): 5607674
TCBID TJCN TOWNR TOFRK TFH TFP TLH TLP TSMRT TRXP TSTO
78 4 14 8 #20026200127 #27 #30000201103 #101607 107 #0 3600000
TERR TSTAT TVTL
#0 #277164 #0
TRIS TRLFT TRLAK TRWND TRLWN TRURP TRBS
21128641 21132187 21132187 2465 21134652 21128641 472
TCRCV TCRPC TCDUP TCIGN TCROS TCRZW TCEWN TCPCC TCRST TCRPU TCRUR
158 709 495 0 0 0 0 0 0 156 0
TSIS TSLFT TSSEQ TSWND TSURP TSBYT TSCB TSCPK
933691392 933691537 933691537 1932 0 0 #0 #0
TCSND TCSPC TCRXP TCRXF TCPZA TCFWN TCFWT TCSPU TCSUR
113 697 1 0 101 1 187 113 0
TCICM TCISQ TCIRD TCFWP
0 0 0 3
TSMXS TCRTM TCATM TCLTM TCBTP TSPRB
964 2440011 2440011 47633921 47633921 2440011
TCSAG TCFAK TIFDF TTTL TTOS TABTF TCABI
0 0 0 60 #0 #0 0
e quitting...
@

If that isn't enough, a packet trace might show what is happening.
The easiest way for a "lowly user" to get one, if the TOPS20 is
connected to an 1822 net, is to use the TCPU program. It creates a
logical host and will pass (tcp) packets between two other hosts,
recording them in the process. Instead of A telneting to B, tell TCPU
to pass packets between A and B, then telnet from A to the logical
host. Note that in this case, netiher A or B need be a TOPS20, but
the route that the packets takes will be longer (through the 20 such
as those at BBN), and there will be a little added delay (TCPU is a
user-level program). [A wheel can get a packet trace of any/all
pcakets through a 20 without a user's cooperation.]

Charlie
PS: See BBN Report 5925 for details and examples of the above.



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